A model system consisting of: 1. fresh secondary cultures of fibroblasts from mouse embryo(Balb C); 2. Balb C fibroblasts transformed with wild-type SV40 (VLM cells); 3. Balb C cells transformed with tsA mutant SV40; 4. Spontaneous transformants of Balb C cells is being used to investigate the following: 1. Distribution of cell surface sialic acid residues and the relation of these anions to Con A binding site distribution in order to elucidate mechanisms of Con A agglutinability and altered adhesive characteristics of transformed cells. 2. Effect of pH on cell shape and binding side distribution. 3. Effect of increase in intracellular calcium levels on cell surface phenomena. 4. Effect of incorporation of various fatty acids into membrane phospholipids. 5. Time course of change in morphology and CABS distribution as a function of temperature in tsA mutant transformed cells.